U.S. patent number 6,049,145 [Application Number 08/888,391] was granted by the patent office on 2000-04-11 for tamper proof safety circuit.
This patent grant is currently assigned to Motorola, Inc.. Invention is credited to Micheal M. Austin, Kevin D. Page.
United States Patent |
6,049,145 |
Austin , et al. |
April 11, 2000 |
Tamper proof safety circuit
Abstract
An electronic device (100) includes electrical circuitry (130),
a housing (105) in which the electronic circuitry (130) is
situated, a cover (110) for enclosing the electrical circuitry
(130) within the housing (105), and a tamper proof safety circuit
(120) coupled to the electrical circuitry (130) for rendering the
electronic device (100) inoperable when the housing (105) and cover
(110) are disassembled.
Inventors: |
Austin; Micheal M. (Lilburn,
GA), Page; Kevin D. (Plantation, FL) |
Assignee: |
Motorola, Inc. (Schaumburg,
IL)
|
Family
ID: |
25393101 |
Appl.
No.: |
08/888,391 |
Filed: |
July 7, 1997 |
Current U.S.
Class: |
307/150;
429/163 |
Current CPC
Class: |
H01M
10/48 (20130101); H01M 10/4257 (20130101); H04M
1/0262 (20130101); H02J 7/0029 (20130101); H01M
50/209 (20210101); Y02E 60/10 (20130101); H01M
50/572 (20210101) |
Current International
Class: |
H01M
10/42 (20060101); H01M 10/48 (20060101); H01M
2/10 (20060101); H02J 7/00 (20060101); H04M
1/02 (20060101); H01M 2/20 (20060101); H01M
2/34 (20060101); H02J 007/00 () |
Field of
Search: |
;307/150,119,112,116
;429/116,7,65,163 ;340/573 ;379/38,39 ;200/61.18 ;361/749,777
;257/922 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Elms; Richard T.
Attorney, Agent or Firm: Farley; Felipe J. Burrus, IV;
Philip H.
Claims
What is claimed is:
1. A battery pack comprising:
electrical circuitry;
a housing in which the electrical circuitry is situated;
a cover for enclosing the electrical circuitry within the
housing;
means for attaching the electrical circuitry to the cover;
a flexible substrate on which the electrical circuitry is
mounted;
a battery cell coupled to electrical circuitry by a flexible
substrate;
wherein a cutout in the flexible substrate partially surrounds a
portion of the electrical circuitry;
whereby disassembly of the cover from the housing can cause tearing
of the cutout, which opens the electrical circuitry, rendering the
battery pack inoperable.
2. The battery pack of claim 1, wherein the flexible substrate
includes a metallized portion in which the cutout is located.
3. The battery pack device of claim 1, wherein the attaching means
comprises an adhesive.
4. An electronic device comprising a battery pack having:
electrical circuitry;
a housing in which the electrical circuitry is situated;
a cover for enclosing the electrical circuitry within the
housing;
means for attaching the electrical circuitry to the cover;
a flexible substrate on which the electrical circuitry is
mounted;
a cell upon which is attached the flexible substrate;
wherein a cutout in the flexible substrate partially surrounds a
portion of the electrical circuitry;
whereby disassembly of the cover from the housing can cause tearing
of the cutout, which opens the electrical circuitry, rendering the
battery pack inoperable.
Description
TECHNICAL FIELD
This invention relates in general to electronic devices, and more
specifically to electronic devices that include safety
circuits.
BACKGROUND OF THE INVENTION
Current market demands for small, lightweight electronic devices,
such as cellular telephones, have required that batteries for such
devices also become smaller and lighter in weight. As a result,
many battery packaging designs have incorporated the use of
extremely thin packaging in the form of covers, housings, and
integral cover/labels that can be removed or peeled open without
difficulty. Though the packaging of a battery is sometimes
destroyed upon disassembly, the battery can still remain
electrically functional with its active circuitry fully exposed.
This represents a significant safety risk, especially when an
opened battery contains lithium cells or high energy super
capacitors.
Thus, what is needed is an improved tamper proof safety circuit for
use in electronic devices such as batteries.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of an electronic device that includes a
tamper proof safety circuit according to the present invention.
FIG. 2 is a top view of a flexible substrate that incorporates the
tamper proof safety circuit of FIG. 1 according to the present
invention.
FIG. 3 is a top view of the flexible substrate of FIG. 2 after the
electronic device of FIG. 1 has been impermissibly opened.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While the specification concludes with claims defining the features
of the invention that are regarded as novel, it is believed that
the invention will be better understood from a consideration of the
following description in conjunction with the drawing figures, in
which like reference numerals are carried forward.
FIG. 1 is an exploded view of an electronic device 100, such as a
primary battery pack or a secondary battery pack, a cellular
telephone, or a selective call receiver, that includes a tamper
proof safety circuit 120 rendering the device 100 inoperable in the
event of unauthorized disassembly. The electronic device 100
includes a housing 105 and a cover 110 which are held together,
such as by ultrasonic welding, heat seal processes, adhesive
bonding, rivets, or mechanical latches, to enclose electrical
circuitry 130 of the electronic device 100. When the device 100
comprises a battery, at least one battery cell 115 is included. The
electrical circuitry 130 can be coupled to the cell 115 by a
flexible substrate 125 to which the circuitry 130 is mounted in a
conventional manner.
According to the present invention, the tamper proof safety circuit
120, which is preferably an integral part of the flexible substrate
125, permits normal operation of the electronic device 100 as long
as the cover 110 and the housing 105 remain sealed together.
However, upon unauthorized removal of the cover 110 from the
housing 105, the tamper proof safety circuit 120 is torn from the
flexible substrate 125 to inactivate the electronic device 100. As
a result, disassembly of the device 100 conveniently prevents
situations in which exposed, potentially unsafe circuitry remains
active, thereby minimizing the likelihood of harm to the user in
the event of device tampering.
The operation of the tamper proof safety circuit 120 can be better
understood by referring to FIG. 2, which is top view of the
flexible substrate 125. As shown, the substrate 125 includes
metallization 135 which electrically couples the circuitry 130 to
the battery cell 115 (FIG. 1) via the safety circuit 120.
Preferably, the safety circuit 120 includes a metallized portion
210 that extends into an area of the substrate 125 that is
partially surrounded by a cutout 205 in the flexible substrate 125.
In other words, portions of the flexible substrate 125 surrounding
the metallized portion 210 have been removed to form a moveable
flap that is connected to other regions of the substrate 125 at
only a single end 220. According to the present invention, the
moveable flap adheres to the cover 110 (FIG. 1) when the device 100
is assembled. This could be done, for instance, by coating a top
surface of the flap with an adhesive 215 that sticks to the cover
100, by riveting the flap to the cover 100, or by providing a
mechanical clasp (not shown) on the cover 100 to grasp the flap
once the device 100 is assembled.
According to the present invention, unauthorized removal of the
cover 110 from the housing 105 will pull up the flap of the
flexible substrate 125 and rip the tamper proof safety circuit 120
from the substrate 125, as shown in FIG. 3. Once the tamper proof
safety circuit 120 has been torn from the substrate 125 by
tampering, the metallized portion 210 (FIG. 2) that previously
connected the battery cell 115 (FIG. 1) to the electrical circuitry
130 will no longer be present to provide the electrical connection,
leaving a hole 305 torn in the flexible substrate 125. As a result,
tampering advantageously renders the electronic device 100
inoperable, preventing situations in which the user could be harmed
by exposed, active circuitry.
Preferably, the electronic device 100 is able to be opened by an
authorized repairperson without tearing the tamper proof safety
circuit 1210 from the flexible substrate 125. By way of example,
returning to FIG. 2, the device 100 could be opened by removing the
cover 110 in the direction indicated by the arrow 230 and
disengaging the flap from the cover 110. In the case where adhesive
215 is used to hold the flap to the cover 110, this could be done
by inserting a device (not shown) to hold the flap down while the
cover 110 is peeled from the adhesive coated flap. When other
coupling devices are used, other methods, such as removal of a
rivet, could be used to disengage the flap from the cover 110.
For disposable electronic devices 100 that are not intended to be
repaired, a repair method may not be necessary. In this situation,
cutouts could be formed in the flexible substrate 125 on both sides
of the attached region 220 of the tamper proof safety circuit 120
so that removal of the cover 110 in the direction 230 also causes
the tamper proof safety circuit 120 to be lifted away and torn from
the substrate 125.
In summary, the electronic device described above includes a tamper
proof safety circuit integrally formed into a flexible substrate of
the device. The tamper proof safety circuit is formed by
surrounding certain metallized portions of the electronic circuitry
with cutouts in the flexible substrate to form a flap. The flap is
attached to the cover of the electronic device when assembled so
that, when the cover is impermissibly removed, the flap is lifted
away from the flexible substrate to tear the tamper proof safety
circuit from the device, rendering the device inoperable. The
likelihood of harm to the user from electrically active, exposed
circuitry is therefore minimized.
It will be appreciated by now that there has been provided an
improved tamper proof safety circuit for electronic devices.
* * * * *